Baking without a recipe

Everyone says baking is an exact science, and it is because of the reactions between the different ingredients. But it is possible to change a recipe because baking is really all about the correct ratios. For example, cookie dough, or, as I posted before, 1-2-3 dough, is a ratio of 1 part butter, 2 parts sugar, and 3 parts flour. With adding some eggs, some baking powder, and some flavor (such as vanilla extract) and you’ve got a cookie dough. I used this recipe to make cookie dough at work without a written recipe. I used 1 cup of butter, 2 cups of sugar (cream together); 2 eggs, added one at a time; a little vanilla extract, a pinch of salt, and 3 cups of flour (mix until all ingredients combine). I was making Snickerdoodle cookies, so I added some cinnamon. I also made peanut butter cookies using 1/3 cup peanut butter and 2/3 cup butter. All of the other ingredients remained the same. This is the first time I made cookie dough without following a recipe. I was quite proud of myself because of this. I will see exactly how well I did once I try baking them off, but I think it will be okay. If it does work out okay, I will definitely be more confident in my baking abilities and about how much going to pastry school has really taught me!